Robotic arm for patient positioning assembly

ABSTRACT

A robotic patient positioning assembly including a patient treatment couch, and a robotic arm coupled to the patient treatment couch. The robotic arm is configured to move the patient treatment couch along five rotational degrees of freedom and one substantially vertical, linear degree of freedom.

RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/417,003, filed Mar. 9, 2012, which is a continuation of U.S. patentapplication Ser. No. 11/129,122, filed May 13, 2005, now U.S. Pat. No.8,160,205, issued Apr. 17, 2012, which is a continuation in part of U.S.application Ser. No. 10/881,315, filed Jun. 30, 2004, now U.S. Pat. No.7,860,550, issued Dec. 28, 2010, which claims the benefit of U.S.Provisional Application No. 60/560,318, filed Apr. 6, 2004, which areincorporated by reference herein.

TECHNICAL FIELD

Embodiments of the present invention pertain to the field of patientpositioning assembly for medical operations.

BACKGROUND

Conventional robots are designed to do exactly the same thing over andover again, such as in an assembly line for assembly. These robots areprogrammed and configured to repeat a given motion to perform a specificfunction. Robots are often implemented to perform a lot of functions,more efficiently, and often more precisely than humans.

Conventional robots, typically, include one or two robotic arms. Theserobotic arms can have multiple segments that help facilitate movement indiffering degrees of freedom (DOF). Some conventional robots employ acomputer to control the segments of the robotic arm by activatingrotation of individual step motors connected to corresponding segments.Other designs may use hydraulics or pneumatics to actuate movement inthe arm segments. Computers allow precise, repeatable movements of therobotic arm.

Prior Selectively Compliant Articulated Robot Arm (SCARA) robots operatewith 4 or fewer degrees of freedom (“DOF”). In other words, theserobotic arms are designed to move along 4 or fewer axes. A typicalapplication for a conventional robotic arm is that of pick-and-placetype machine. Pick-and-place type machines are used for automationassembly, automation placing, printed circuit board manufacturing,integrated circuit pick and placing, and other automation jobs thatcontain small items, such as machining, measuring, testing, and welding.These robotic arms include an end-effector, also known as roboticperipheral, robotic accessory, robot or robotic tool, end of arm (EOA)tooling, or end-of-arm device. The end-effector may be an implement suchas a robotic gripper, press tool, paint gun, blowtorch, deburring tool,arc welding gun, drills, etc. These end-effectors are typically placedat the end of the robotic arm and are used for uses as described above.One common end-effector is a simplified version of the hand, which cangrasp and carry different objects. Such end effectors typically supportmaximum payloads ranging from 3 kg-20 kg (6.61-44.09 pounds).

Some conventional robots have been employed for patient positioning forsuch applications as external radiotherapy. One such patient positionsystem is the Harvard Cyclotron Laboratory robotic table/chair for largefields. This design is used for a fixed horizontal proton beam treatmentroom based on a turntable platform, air pads, and four independentlydriven legs. Another patient position system is the stereotactic device“Star” for radiosurgery used at the proton line of Harvard CyclotronLaboratory. This “Star” design is based on an air-suspension system anda double rotation of the base around a vertical axis and the patientaround its own horizontal main axis.

Another patient positioning system uses a robotic chair for treatmentsof ocular and head targets based on a six DOF parallel link robot and arotational platform. Another example is a table attached to a patientpositioner for the gantry rooms of the Northeast Protontherapy Center atBoston. This particular design is based on a linear robot with 6 DOF.The 6 DOF of this design, however, include at least three (3) linearaxes. These three linear axes facilitate only translational movements.Additionally, this design seems to only facilitate rotational movementin one DOF with respect to the movement of the attached table, andmoreover this robot is attached to the floor or in a pit under thefloor.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are illustrated by way of example,and not by way of limitation, in the figures of the accompanyingdrawings and in which:

FIG. 1 illustrates a schematic block diagram of one embodiment of arobotic patient positioning assembly for therapeutic radiationtreatment.

FIG. 2A illustrates one embodiment of a robotic patient positioningassembly including a robotic arm having five rotational degrees offreedom and one substantially vertical, linear degree of freedom.

FIG. 2B illustrates one embodiment of a patient treatment couchincluding a mounting plate.

FIG. 2C illustrates a cross sectional view of one embodiment of apatient treatment couch.

FIG. 2D illustrates one embodiment of a patient treatment couchincluding a mounting plate, tilt sensor, and a dampener.

FIG. 2E illustrates one embodiment of a track mount assembly.

FIG. 2F illustrates one embodiment of a deflection error of a patienttreatment couch and the vertically mounted robotic arm.

FIG. 3A illustrates one embodiment of a robotic patient positioningassembly having a robotic arm having six rotational degrees of freedomand one substantially horizontal, linear degree of freedom.

FIG. 3B illustrates one embodiment of patient treatment couch coupled tothe robotic arm of FIG. 3A.

FIG. 4A illustrates one exemplary position of the robotic patientpositioning assembly having five rotational degrees of freedom and onesubstantially vertical, linear degree of freedom together with arobot-based linear accelerator system.

FIG. 4B illustrates another exemplary position of the robotic patientpositioning assembly having five rotational degrees of freedom and onesubstantially vertical, linear degree of freedom together with arobot-based linear accelerator system.

FIG. 4C illustrates a top-down view of a total usable surface area atherapeutic radiation source having a robotic arm mounted to a firstside of a conventional treatment table.

FIG. 4D illustrates a top-down view of the total usable surface area ofthe therapeutic radiation source having the robotic arm mounted to asecond side of the conventional treatment table.

FIG. 4E illustrates a top-down view of a total usable surface area ofone embodiment of a therapeutic radiation source and a patient treatmentcouch.

FIG. 4F illustrates an alternative embodiment of a robot arm mounting toa couch.

FIG. 4G illustrates a side and top view of one embodiment of the roboticarm mounting of to the couch of FIG. 4F in relation to an imagingsystem.

FIG. 5 illustrates one embodiment of a schematic diagram of a handhelduser interface unit.

FIG. 6 illustrates an exemplary embodiment of a user interface screen,launched onto a treatment delivery display screen.

FIG. 7 illustrates a one embodiment of a method for positioning apatient treatment couch using a robotic arm.

FIG. 8 illustrates another embodiment of a method for positioning apatient treatment couch using a robotic arm and a robot-based linearaccelerator system.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forthsuch as examples of specific components, devices, methods, etc., inorder to provide a thorough understanding of the present embodiments. Itwill be apparent, however, to one skilled in the art that these specificdetails need not be employed to practice the present embodiments. Inother instances, well-known materials or methods have not been describedin detail in order to avoid unnecessarily obscuring the presentembodiments.

A robotic patient positioning assembly is described for adjustingpatient position during, for example, therapeutic radiation treatmentusing a therapeutic radiation treatment system. The robotic patientpositioning assembly includes an articulated robotic arm that includes atrack mount assembly to facilitate movement of a patient on a patienttreatment couch (e.g., table or chair) in a three-dimensional (3D)space, as well raising and lowering the patient to high and lowpositions without compromising the flexibility or positioning intranslational and rotational movements. The track mount assembly may bevertically mounted, for example, to a vertical side of a column.

The robotic arm can position a patient treatment couch attached to therobotic arm in five DOF, and one substantially vertical, linear DOF. Thefive DOF include two rotational axes for translational movements alongmutually orthogonal x-, and y-horizontal coordinate axes; and threerotational axes for roll-, pitch-, and yaw-rotational movements aboutx-, y-, and z-axes, respectively. The one substantially vertical, linearDOF includes a substantial linear axis for translation along asubstantially vertical line in a z-coordinate axis perpendicular to thehorizontal, x-, and y-coordinate axes. In one embodiment, the patienttreatment couch and the vertically mounted robotic arm may enablesupport of a patient load up to five hundred pounds (500 lbs) with adeflection of approximately zero to five millimeters (0 to 5 mm).

In another embodiment, the robotic arm includes an additional platemember attached between the shoulder assembly and the track mountassembly to provide an additional rotational DOF, totaling sixrotational DOF and one substantially vertical, linear DOF. The six DOFinclude three rotational axes for translational movements along mutuallyorthogonal x-, y-, and z-coordinate axes; and three rotational axes forroll-, pitch-, and yaw-rotational movements about x-, y-, and z-axes,respectively. The one substantially vertical, linear DOF includes asubstantial linear axis for translation along a substantially verticalline in a z-coordinate axis perpendicular to the horizontal, x-, andy-coordinate axes.

FIG. 1 illustrates a schematic block diagram of one embodiment of arobotic patient positioning assembly that adjusts a patient's positionunder computer control, during therapeutic radiation treatment. In thisembodiment, the robotic patient positioning assembly 100 includes: 1) apatient treatment couch 103 for supporting and positioning a load, suchas a patient during therapeutic radiation treatment, and 2) a roboticarm 102, which facilitates positioning of the patient treatment couch infive rotational DOF and one substantially vertical, linear DOF in a 3Dworkspace or operating envelop in a treatment room. The controller 101of FIG. 1 is coupled to the robotic arm 102, sensor system 104, userinterface 105, therapeutic radiation treatment system 106, and imagingsystem 107. The robotic arm 102 is coupled to the patient treatmentcouch 103.

The robotic patient positioning assembly 100 may further include asensor system 104 for detecting the position of the patient treatmentcouch 103; a controller 101 for controlling the motion of the roboticarm 102 and patient treatment couch 103; a user interface unit 105,which allows a user to manually control the motion of the robotic arm102 and the patient treatment couch 103; and a therapeutic radiationtreatment system 106. The controller 101 may be operatively coupled tothe sensor system 104 and the user interface unit 105 of the roboticpatient positioning assembly 100 in order to calculate the position ofthe patient treatment couch 103 relative to the treatment room or otherpredefined treatment coordinate system based on the data received fromthe sensor system 104. The controller 101 may also operate to controlthe motion of the robotic patient positioning assembly 100 in a way thata treatment target within the patient's anatomy remains properly alignedwith respect to a treatment beam source of a therapeutic radiationtreatment system 106 throughout the treatment procedure. Controller 101may also be used to operate the therapeutic radiation treatment system106. In one embodiment, the therapeutic radiation treatment system 106may be a frameless, image-guided robot-based therapeutic radiationtreatment system utilizing a linear accelerator (“linac”), such as theCyberKnife® system developed by Accuray, Inc. of California.Alternatively, the therapeutic radiation treatment system 106 may be agantry-based (iso-centric) treatment system or other types of medicaloperation systems. The controller 101 may also communicate with thetherapeutic radiation treatment system 106, receiving pre-treatment scandata representative of one or more pre-treatment scans of a treatmenttarget within the patient. The pre-treatment scans may show the positionand orientation of the target with respect to a pre-treatment coordinatesystem. The controller 101 may also receive from the imaging system 107image data representative of real time or near real time images of thetarget. The image data may contain information regarding the real timeor near real time position and orientation of the target with respect toa treatment coordinate system. The treatment coordinate system and thepre-treatment coordinate system are related by known transformationparameters.

The controller 101 may include an input module for receiving 1)pre-treatment scan data representative of pre-treatment scans of thetarget, and 2) real time or near real time image data representative ofreal time or near real time images of the target. The pre-treatmentscans show the position and orientation of the target with respect tothe pre-treatment coordinate system. The near real-time images, taken bythe imaging system 107 under the command of the controller 101, show theposition and orientation of the treatment target with respect to thetreatment coordinate system. The treatment coordinate system and thepre-treatment coordinate systems are related by known transformationparameters. The controller 101 includes a TLS (target location system)processing unit that computes the position and orientation of thetreatment target in the treatment coordinate system, using thepre-treatment scan data, the real time or near real time image data, andthe transformation parameters between the pre-treatment coordinatesystem and the treatment coordinate system. The processing unit of thecontroller 101 may also compute the position and orientation of theiso-center of the therapeutic radiation treatment system 106.

The sensor system 104 of the robotic patient positioning assembly 100for detecting the position of the patient treatment couch 103 may be aresolver-based sensor system. Alternatively, other sensor systems knownby those skilled in the art may be used, such as an inertial sensorattached to the patient treatment couch 103 for sensing the motions ofthe patient treatment couch 103, or an infrared triangulation system, ora laser scanning system or an optical tracking system disposed withinthe treatment room for detecting the position of the patient treatmentcouch 103 relative to the treatment room or other treatment coordinatesystem, or an optical encoder.

An exemplary laser scanning system may scan the treatment roomapproximately 60×/sec to determine the position of the patient treatmentcouch 103. The laser scanning system may include devices performing asingle plane scanning, or two-plane scanning, or multiple-planescanning. Correspondingly, the controller 101 may be loaded withsoftware adapted for receiving information from the sensor system 104and calculating the position of the patient treatment couch 103, as wellas the therapeutic radiation treatment system 106, so that the roboticpatient positioning assembly 100 including the controller 101 alwaysknows the position of the patient treatment couch 103. The controller101 may be programmed to automatically or periodically calibrate thepatient treatment couch 103 with the therapeutic radiation source of thetherapeutic radiation treatment system 106. In an alternate embodiment,the sensor system 104 includes a magnetic tracking system for trackingthe position of the patient treatment couch 103 relative to thetreatment coordinate system. The magnetic tracking system preferablyincludes at least one transducer attached to the patient treatment couch103.

The controller 101 may be adapted to detect a misalignment of thetreatment target with the iso-center of the linac system caused bypatient's movement by comparing the position of the treatment targetwith the iso-center of the linac system, and generate motion commandsignals for implementing corrective motions of the robotic patientpositioning assembly 100 for aligning the treatment target with respectto the radiation treatment source of the therapeutic radiation treatmentsystem 106.

In another embodiment, the corrective motions of the robotic patientpositioning assembly 100 may accommodate for various motions, such asrespiratory motion; cardiac pumping motion of the patient's heart;sneezing, coughing, or hiccuping; and muscular shifting of one or moreanatomical members of the patient.

In another embodiment, the robotic patient positioning assembly 100including the controller 101 may be adapted to detect and accommodatechanges in tumor geometry that may be caused by tissue deformation bycomparing the real time or near real time image with the pre-treatmentimage and repositioning the patient using the patient treatment couch103 and/or the radiation source of the therapeutic radiation treatmentsystem 106 (in a robot-based therapeutic radiation treatment system), oradjusting the positions of the patient treatment couch 103 and theradiation source of the therapeutic radiation treatment system 106 tocorrespond to the treatment plan.

The controller 101 includes software for establishing and maintaining areliable communication interface with the patient treatment couch 103.The software uses the interface specifications developed for the patienttreatment couch 103. The controller 101 further includes software forconverting the patient position and orientation information from theimaging system 107 to appropriate units of movement in the degrees offreedom of motion capability of the patient treatment couch 103. Thecontroller 101 may include software for providing a user interface unit105 to the therapeutic radiation treatment system user control console,to monitor and initiate the motion of the robotic patient positioningassembly 100 for positioning the patient. The controller 100 may alsoinclude software for detecting, reporting, and handling errors incommunication or software control of the patient treatment couch 103.

The controller 101 may include at least one user interface unit, such asuser interface unit 105, for enabling the user to interactively controlthe motions or corrective motions of the robotic patient positioningassembly 100, by implementing one or more user-selectable functions. Inone embodiment, the user interface unit 105 may be a handheld userinterface unit or remote control unit. Alternatively, the user interfaceunit 105 may be a graphical user interface (GUI).

The communication links between the controller 101 and other componentsof the robotic patient positioning assembly 100 (e.g., the robotic arm102, patient treatment couch 103, sensor system 104, user interface 105,therapeutic radiation treatment system 106, and imaging system 107) maybe wired links or wireless links, with a bandwidth necessary formaintaining reliable and timely communications.

In one embodiment, the therapeutic radiation treatment system 106 may bea radiosurgery system, such as the CyberKnife® radiosurgery system. Theradiosurgery system may include a robot, having an articulated roboticarm; a therapeutic radiation source, mounted at a distal end of thearticulated robotic arm, for selectively emitting therapeutic radiation;an x-ray imaging system 107; and a controller. In one embodiment, thetherapeutic radiation source may be an x-ray linac. The x-ray imagingsystem 107 generates image data representative of one or more real timeor near real time images of the target. The x-ray imaging system 107 mayinclude a pair of diagnostic x-ray sources, and a pair of x-ray imagedetectors 408 (or cameras), each detector located opposite an associatedx-ray source. The patient treatment couch 103 (or treatment table)supports the patient during treatment, and may be positioned between thetwo x-ray cameras and their respective diagnostic x-ray sources of theimaging system 107.

The imaging system 107 generates, in real time or near real time, x-rayimages showing the position and orientation of the target in a treatmentcoordinate frame. The controller 101 may contain treatment planning anddelivery software, which may be responsive to pre-treatment scan data CT(and/or MRI data, PET data, ultrasound scan data, and/or fluoroscopyimaging data) and user input, to generate a treatment plan consisting ofa succession of desired beam paths, each having an associated dose rateand duration at each of a fixed set of treatment positions or nodes. Inresponse to the controller's directions, the robotic arm moves andorients the x-ray linac, successively and sequentially through each ofthe nodes, while the x-ray linac delivers the required dose as directedby the controller. The pre-treatment scan data may include, for example,CT scan data, MRI scan data, PET scan data, ultrasound scan data, and/orfluoroscopy imaging data.

Prior to performing a treatment on a patient therapeutic radiationtreatment system 106, the patient's position and orientation within theframe of reference established by imaging system 107 must be adjusted tomatch the position and orientation that the patient had within the frameof reference of the CT (or MRI or PET or fluoroscopy) scanner thatprovided the images used for planning the treatment. In one exemplaryembodiment, this alignment may be performed to within tenths of amillimeter and tenths of a degree for all five or six rotational degreesof freedom and the one substantially vertical, linear degree of freedom.

Although the robotic arm 102 and patient treatment couch 103 may bedescribed herein in relation to an image-guided robot-based therapeuticradiation treatment system (and, in particular, the CyberKnife's®system), the robotic arm 102 and patient treatment couch 103 may also beused with the other types of systems such as gantry-based (iso-centric)treatment systems. It should also be appreciated that the roboticpatient positioning assembly 100 may alternatively be used for othermedical applications, for example, as an operating room (OR) table, oras a supporting device in CT scanning or in MRI process, and the like.

FIG. 2A illustrates one embodiment of a robotic patient positioningassembly including a robotic arm having five rotational degrees offreedom and one substantially vertical, linear degree of freedom. Therobotic patient positioning assembly of FIG. 2A includes a robotic arm202 having a wrist assembly 220, an elbow assembly 230, a shoulderassembly 240, a track mount assembly 250, and a track 260; a patienttreatment couch 103; and a column 270. Patient treatment couch 103 maybe rotatably attached to the wrist assembly 220, which includes atool-yaw joint, a tool-pitch joint, and a tool-roll joint. The tool-yawjoint of wrist assembly 220 may be coupled to mounting plate 211, whichmay be attached to the bottom of the patient treatment couch 103. Thetool-yaw joint of wrist assembly 220 facilitates rotational movement ofthe patient treatment couch 103 in a yaw-rotation along the z-axis, axis6 of FIG. 2A. The tool-pitch joint may be coupled to the tool-yaw jointand facilitates rotational movement of the patient treatment couch 103in a pitch-rotation along the y-axis, axis 5 of FIG. 2A. The tool-rolljoints may be coupled to the tool-pitch joint and facilitates rotationalmovement of the patient treatment couch 103 in a roll-rotation along thex-axis, axis 4 of FIG. 2A.

The elbow assembly 230 may be coupled to the tool-roll joint of wristassembly 220. The elbow assembly 230 may include three drive shafts andthree motors. In one embodiment, the motors discussed herein may be stepmotors. Alternatively, the motors may be servo motors or other motorsknown by those of ordinary skill in the art. The first drive shaft maybe coupled to the tool-yaw joint and the first motor. The first motorand drive shaft drive rotational movement of patient treatment couch 103along the yaw axis, axis 6. The second drive shaft may be coupled to thetool-pitch joint and the second motor. The second motor and drive shaftdrive rotational movement of the patient treatment couch 103 along thepitch axis, axis 5. The third drive shaft may be coupled to thetool-roll joint and the third motor. The third motor and drive shaftdrive rotational movement of the patient treatment couch 103 along theroll axis, axis 4. In one exemplary embodiment, the elbow assembly 230is ten inches (10″) in diameter at the distal end that connects to thetool-roll joint of the wrist assembly 220. Alternatively, the elbowassembly 230 may have a diameter being approximately in a range of threeto twenty inches (3″-20″). Alternatively, the elbow assembly 230 mayhave another shape than circular, for example, rectangular, oval, orother known shapes, and the elbow assembly 230 may have a minimummeasurement of its cross section between three (3″) to twenty (20″)inches.

The shoulder assembly 240 may be coupled to the elbow assembly 230 by anelbow joint and to the track mount assembly 250 by a shoulder joint. Theelbow joint includes an elbow gearbox, which may be configured to driverotational movement of the elbow assembly 230 of the robotic arm 202 ina rotational axis, axis 3 of FIG. 2A. The shoulder joint includes ashoulder gearbox, which may be configured to drive rotational movementof the shoulder assembly 240 of the robotic arm 202 in a rotationalaxis, axis 2 of FIG. 2A. The elbow and shoulder gearboxes of theshoulder and elbow assemblies 230 and 240 facilitate translationalmovement of the patient treatment couch 103 in a two-dimensionalhorizontal plane, for example, in the (x-, y-) plane parallel with thefloor. In one embodiment, the elbow and shoulder gearboxes haveapproximately a two hundred to one gear reduction ratio (200:1). The200:1 gear reduction ratio of the elbow and shoulder gearboxes mayenable support of a patient load up to five hundred pounds within adeflection error 261 on the patient treatment couch 103, beingapproximately in a range of zero to sixty millimeters (0 to 60 mm). Inone exemplary embodiment, the deflection error 261 is approximately zeroto five millimeters (0 to 5 mm). Alternatively, the gear reductionratios may have a range of approximately ten to one gear reduction ratio(10:1) to approximately six hundred to one gear reduction ratio (600:1).It should be noted that the structure described herein when referring tosupporting a patient load up to five hundred pounds (500 lbs) maysupport four times (4×) the weight of the patient load in order tocomply with safety standards. Further, although illustrated using arobotic arm having five rotational degrees of freedom and onesubstantially vertical, linear degree of freedom, deflection error 261of FIG. 2F applies to the other embodiments of the robotic arm havingsix rotational degrees of freedom and one substantially vertical, lineardegree of freedom described herein.

In one embodiment, the controller 101, the shoulder and elbow gearboxesof the robotic arm 202, the track mount assembly 250, and the wristassembly 220, may include components manufactured by KUKA Roboter GmbHof Germany.

The track mount assembly 250 may be coupled to a track 260 and to theshoulder joint of the shoulder assembly 240. The track mount assembly250 and track 260 facilitate translational movement of the patienttreatment couch 103 in a substantially vertical, linear axis, axis 1 ofFIG. 2A. The substantially vertical, linear axis (z-) may besubstantially perpendicular to the two dimensional horizontal plane (x-,y-). In one embodiment, the track may be vertically oriented, forexample, vertically mounted to a vertical side of column 270. The column270 may be secured or mounted to the floor of the treatment room duringtherapeutic radiation treatment or below the floor in a pit. In anotherembodiment, column 270 may be secured or mounted to the ceiling of thetreatment room during therapeutic radiation treatment. Alternatively,the track 260 may be vertically mounted to other structures known tothose skilled in the art, such as a wall, pedestal, block, or basestructure. Column 270 includes a column depth 271, and a column width272. In one embodiment, the column depth 271 is at least approximatelyten inches (10″) and the column width 272 is at least approximatelyfifteen inches (15″). In one exemplary embodiment, the column depth 271is approximately seventeen inches (17″) and the column width 272 isapproximately twenty-two inches (22″). In one embodiment, the column 270has at least a principal moment of inertia about the x-axis ofapproximately 800 in⁴. In one exemplary embodiment, the principal momentof inertial about the x-axis is approximately 1200 in⁴.

The above mentioned arrangement of the wrist assembly 220, elbowassembly 230, shoulder assembly 240, track mount assembly 250, and track260 facilitate the positioning of the patient treatment couch 103 usingfive rotational degrees of freedom and one translational substantiallyvertical, linear degree of freedom. The five rotational and onetranslational substantially vertical, linear DOF of the robotic arm 202of the robotic patient positioning assembly 100 may position a patienton the patient treatment couch 103 in substantially any place in adesired treatment area, such as a workspace within the mechanical rangeof motion of the robotic arm 202. The robotic arm 202 may position thepatient treatment couch 103 to have a tool center position (TCP) oriso-center in multiple locations within the workspace or treatment area.The robotic arm 202 may also provide loading/unloading positions for aparticular patient, as discussed below. The robotic arm 102 may beconfigured to facilitate motion of the patient treatment couch 103 alongfive rotational DOF and one substantially vertical, linear DOF. In oneexemplary embodiment, the five DOF includes two rotational axes fortranslational movements along mutually orthogonal, horizontal coordinateaxes (x-, and y-); and three rotational axes for roll-, pitch-, andyaw-rotational movements about x-, y-, and z-axes, respectively. The onesubstantially vertical, linear DOF includes a substantial linear axisfor translational movement along a substantially vertical line in acoordinate axis (z-) substantially perpendicular to the horizontalcoordinate axes (x-, and y-).

In one embodiment, the robotic arm 202 includes one or more patienttreatment couch motion actuators for moving the patient treatment couch103, in accordance with directions from the controller 101. A tableinterface module allows the patient treatment couch 103 to interfacewith the sensor system 104, the actuators of the robotic arm 102, thecontroller 101, the therapeutic radiation treatment system 106, and theuser interface unit 105. The electronics module may independently checkpatient treatment couch positions against a model of surroundingobstructions to ensure that the patient treatment couch 103 does notcollide with obstacles during motion of the robotic patient positioningassembly 100.

In the illustrated embodiment of FIG. 2A, the patient treatment couch103 may be a treatment table, although in other embodiments, other typesof support devices (such as a table, chair or bench) may be used.

FIG. 2B illustrates one embodiment of a patient treatment couchincluding a mounting plate. Mounting plate 211 is coupled to the patienttreatment couch 103. In one embodiment, the mounting plate 211 may beattached to the patient treatment couch 103 at an off-center position orpivot point. In one embodiment, the length 215 of the patient treatmentcouch 103 may be approximately in a range of forty-eight inches to onehundred forty-five inches (48″-145″). The width 214 of the patienttreatment couch 103 may be approximately in a range of ten inches andforty-five inches (10″-45″). In one exemplary embodiment, length 215 isapproximately 78 inches and the width 214 is approximately twenty inches(20″).

In one embodiment, the off-center position 217 may be approximately in arange of fifty to seventy-five inches (50″-75″) from one side of thepatient treatment couch 103 (e.g., side that includes the patient headrest) with respect to the length 215 of the patient treatment couch 103.In one exemplary embodiment, the off-center position 217 is fifty inches(50″) from one side of the patient treatment couch 103 with respect tothe length 215 of the patient treatment couch 103. In anotherembodiment, the off-center position 217 is an off-center length distance212 and an off-center width distance 218 from the center position 216 ofthe patient treatment couch 103. In one embodiment, the off-centerlength distance 212 may be approximately in a range of zero to ninetypercent (0-90%) of a distance to one side of the patient treatment couch103 from the center position 216 with respect to the length 215 and theoff-center width distance 218 may be approximately in a range of zero toninety percent (0-90%) of a distance to one side of the patienttreatment couch 103 from the center position 216 with respect to thewidth 214. In an exemplary embodiment, the off-center position 217 isapproximately twenty-one inches (21″) from a center position 216 withrespect to a length 215 of the patient treatment couch 103 andapproximately four inches (4″) from the center position 216 with respectto a width 214 of the patient treatment couch 103. Or in other words,the off-center length distance 212 is twenty-one inches (21″) and theoff-center width distance 218 is 4 inches (4″). In another embodiment,the off-center position 217 may be expressed in terms of percentages,for example, the off-center position 217 may be located withinapproximately 50-85% with respect to the length 215 of the patienttreatment couch 103 and within approximately 0-50% with respect to thewidth 214 of the patient treatment couch 103. Alternatively, themounting plate 211 may be coupled to the patient treatment couch 103 inthe center position 216 with respect to the length 215 and the width 214of the patient treatment couch 103.

The patient treatment couch 103 in one embodiment may have a thickness213 being approximately in a range of 0.75 inches to 3 inches. In oneexemplary embodiment, the patient treatment couch 103 has a thickness213 of approximately 2.25 inches. In another exemplary embodiment, thepatient treatment couch 103 has a thickness 213 of approximately 2.25inches, a length 215 of approximately 77 inches, and a width 214 ofapproximately 20 inches.

FIG. 2C illustrates a cross sectional view of one embodiment of apatient treatment couch. Patient treatment couch 103 may be made ofradiolucent material. In one embodiment, the patient treatment couch 103includes a skin material 256 and a body material 257. In one exemplaryembodiment, the skin material 256 is carbon fiber and the body material257 is foam. Alternatively, other radiolucent material may be used forthe skin and body materials. In one embodiment, the skin material 256includes a skin thickness 258. The skin thickness 258 may beapproximately in a range of thickness of 0.02 to 0.12 inches. In oneexemplary embodiment, the skin thickness may be approximately 0.058inches.

FIG. 2D illustrates one embodiment of a patient treatment couchincluding a mounting plate, tilt sensor, accelerometer, and a dampener.In this embodiment, a dampener 219 is coupled to the mounting plate 211and the patient treatment couch 103. The dampener 219 may includedampening material, such as, rubber or plastic. Alternatively dampener219 may be another device known in the art to reduce or dampenvibrations, such as, a spring type element.

Tilt sensor 280 may be mounted to the patient treatment couch 103. Tiltsensor 280 may be a dual-axis tilt sensor that detects the angle of thepatient treatment couch 103. The tilt sensor 280 may be coupled to thecontroller 101 and may be configured to send information regarding thetilt of the patient treatment couch 103, such as the angle measurementfor one or more axis. The tilt sensor 280 may prevent the patient fromfalling off of the patient treatment couch 103 during treatment. Thetilt sensor 280 may also allow the patient to feel safe from falling offthe patient treatment couch 103. The tilt sensor 280 allows the patienttreatment couch 103 to operate without rails to prevent the patient fromfalling off or being uncomfortable during treatment. In one embodiment,tilt sensor 280 may be a single axis tilt sensor and one or more tiltsensors may be used to detect tilt of the patient treatment couch 103 inthe roll and pitch rotations. In another embodiment, the tilt sensor 280may be a dual axis tilt sensor, which detects and sends information(e.g., angle measurements) to the controller 101 regarding the tiltangle of both the pitch and roll rotations of the patient treatmentcouch 103. Alternatively, other tilt sensors known to those of ordinaryskill in the art may be used, such as, a tri-axis tilt sensor. The tiltsensor 280 may be configured to detect when the roll and/or pitch angleof the patient treatment couch 103 reaches a pre-configured angle and tohalt motion of the patient treatment couch 103 so as to not exceed thatpre-configured angle to prevent the patient from falling off. In oneembodiment, the pre-configured angle may be approximately in a range ofsix to nine degrees (6-9°). In one exemplary embodiment, thepre-configured angle is seven degrees (7°.) Alternatively, otherspecific angles may be used to prevent motion of the patient treatmentcouch 103 to exceed pre-configured angles during its movement in theroll or pitch axes. In one embodiment, the tilt sensor 280 may includecomponents manufactured by Crossbow Inc., of San Jose, Calif.

Accelerometer 281 may be mounted to the patient treatment couch 103.Accelerometer 281 may detect the acceleration of the patient treatmentcouch 103. The accelerometer 281 may be coupled to the controller 101and may be configured to send information regarding the acceleration ofthe patient treatment couch 103. The accelerometer may prevent thepatient from falling off of the patient treatment couch 103 duringtreatment. In one embodiment, the accelerometer 281 may includecomponents manufactured by Crossbow Inc., of San Jose, Calif. In oneembodiment, the robotic patient positioning assembly 100 may includeonly tilt sensor 280. Alternatively, the robotic patient positioningassembly 100 may include only accelerometer 281. It should also be notedthat although not illustrated in the other figures as to not obscure thediscussion of other embodiments, the dampener 219, accelerometer 281,and tilt sensor 280 may be used in other embodiments described herein.

FIG. 2E illustrates one embodiment of a track mount assembly. Trackmount assembly 251 is coupled to the track 260 and shoulder assembly 240of FIG. 2A. It should be noted that description herein with respect tothe structure and operations of the track mount assembly 250 of roboticarm 202 apply to track mount assembly 251. The track mount assembly 251includes a track mount collar 252 and a track mount plate 253. In oneembodiment, the track mount collar 252 and the track mount plate 253 maybe separate components. Alternatively, the track mount collar 252 and atrack mount plate 253 may be one integral piece. Track mount collar 252includes a frontal height 254, and a rear height 255, the rear height255 being closer to the track than the frontal height 254. In oneembodiment, the rear height of the track mount collar 252 may be atleast eleven inches (11″). In another embodiment, the track mount collar252 may taper down in height from the end closest to the track mountplate 253 being greater in height than the end farthest away from thetrack mount plate 253. In such embodiment, the frontal height 254 at theend farthest away from the track mount plate 253 may be at least fiveinches (5″), while the rear height 255 at the end closest to the trackmount plate 253 may be at least eleven inches (11″).

In one embodiment, patient treatment couch 103 coupled to the mountingplate 211 in an off-center position 217 enables support of a patientload up to five hundred pounds within a deflection error 261 ofapproximately zero to five millimeters (0 to 5 mm) of the patienttreatment couch 103. In another embodiment, the thickness 213 of thepatient treatment couch 103 enables support of a patient load up to fivehundred pounds within a deflection error 261 of approximately zero tofive millimeters (0 to 5 mm) of the patient treatment couch 103.Alternatively, both the coupling of the patient treatment couch 103 tothe mounting plate 211 in an off-center position 217 and the thickness213 of the patient treatment couch enables support of a patient load upto five hundred pounds within a deflection error 261 of approximatelyzero to five millimeters (0 to 5 mm) of the patient treatment couch 103.It should be noted that the patient treatment couch 103 and robotic arm202 may support more weight than five hundred pounds.

FIG. 3A illustrates one embodiment of a robotic patient positioningassembly including a robotic arm having six rotational degrees offreedom and one substantially horizontal, linear degree of freedom. Asshown in FIG. 3A, the robotic patient positioning assembly includes arobotic arm 302 having a wrist assembly 220, an elbow assembly 230, ashoulder assembly 240, a plate member 380, a track mount assembly 350,and a track 360; and a patient treatment couch 103 (not illustrated inFIG. 3A). As described above, the patient treatment couch 103 may berotatably attached to the wrist assembly 220, which includes a tool-yawjoint, a tool-pitch joint, and a tool-roll joint. The tool-yaw joint ofwrist assembly 220 may be coupled to mounting plate 211, which isattached to the bottom of the patient treatment couch 103. The tool-yawjoint of wrist assembly 220 facilitates rotational movement of thepatient treatment couch 103 in a yaw-rotation along a yaw axis, axis 6of FIG. 3A. The tool-pitch joint may be coupled to the tool-yaw jointand facilitates rotational movement of the patient treatment couch 103in a pitch-rotation along a pitch axis, axis 5 of FIG. 3A. The tool-rolljoints may be coupled to the tool-pitch joint and facilitates rotationalmovement of the patient treatment couch 103 in a roll-rotation along aroll axis, axis 4 of FIG. 3A.

The elbow assembly 230 may be coupled to the tool-roll joint of wristassembly 220. The elbow assembly 230 includes three drive shafts andthree motors. The first drive shaft may be coupled to the tool-yaw jointand the first motor. The first motor and drive shaft drive rotationalmovement of patient treatment couch 103 along the yaw axis, axis 6 ofFIG. 3A. The second drive shaft may be coupled to the tool-pitch jointand the second motor. The second motor and drive shaft drive rotationalmovement of the patient treatment couch 103 along the pitch axis, axis 5of FIG. 3A. The third drive shaft may be coupled to the tool-roll jointand the third motor. The third motor and drive shaft drive rotationalmovement of the patient treatment couch 103 along the roll axis, axis 4of FIG. 3A. In one exemplary embodiment, the elbow assembly 230 is teninches (10″) in diameter at the distal end that connects to thetool-roll joint of the wrist assembly 220. Alternatively, the elbowassembly 230 may have a diameter that is approximately three to twentyinches (3″-20″). Alternatively, the elbow assembly 230 may have anothershape than circular, for example, rectangular, oval, or other knownshapes, and the elbow assembly 230 may have a minimum measurement of itscross section between three (3″) to twenty (20″) inches. In oneembodiment, the ten inch diameter of the elbow assembly coupled to thepatient treatment couch 103 enables support of a patient load up to fivehundred pounds within a deflection error 261 of approximately zero tofive millimeters (0 to 5 mm) of the patient treatment couch 103.

The shoulder assembly 240 may be coupled to the elbow assembly 230 by anelbow joint and to the track mount assembly 350 by a shoulder joint. Theelbow joint includes an elbow gearbox, which may be configured to driverotational movement of the elbow assembly 230 of the robotic arm in arotational axis, axis 3 of FIG. 3A. The shoulder joint includes ashoulder gearbox, which may be configured to drive rotational movementof the shoulder assembly 240 of the robotic arm in a rotational axis,axis 2 of FIG. 3A. The elbow and shoulder gearboxes of the shoulder andelbow assemblies 230 and 240 facilitate translational movement of thepatient treatment couch 103 in a two-dimensional horizontal plane, forexample, in the (x-, y-) plane parallel with the floor. In oneembodiment, the elbow and shoulder gearboxes have approximately a twohundred to one gear reduction ratio (200:1). The 200:1 gear reductionratio of the elbow and shoulder gearboxes may enable support of apatient load up to five hundred pounds within a deflection error 261 onthe patient treatment couch 103, being approximately in a range of zeroto sixty millimeters (0 to 60 mm). In one exemplary embodiment, thedeflection error 261 is approximately zero to five millimeters (0 to 5mm). Alternatively, the gear reduction ratios may range fromapproximately ten to one gear reduction ratio (10:1) to approximatelysix hundred to one gear reduction ratio (600:1).

The plate member 380 may be coupled to the shoulder joint of theshoulder assembly 240 and rotatably mounted to the track mount assembly350. The plate member includes a gearbox, which may be configured todrive rotational movement of the plate member 380 of the robotic arm ina rotational axis, axis 1 of FIG. 3A. The gearbox of the plate memberfacilitates translational movement of the patient treatment couch 103 ina horizontal plane substantially parallel to the floor. In oneembodiment, the gearbox of the plate member 380 has a gear reductionratio. The gear reduction ratio of the gearbox of the plate member 380may range from approximately two hundred and fifty to one toapproximately three hundred to one (250:1 to 300:1). In one exemplaryembodiment, the gear reduction ratio of the plate member gearbox isapproximately 300:1.

In one embodiment, the track mount assembly 350 has similar dimensionsas set forth in the discussion above with respect to FIG. 2E.Alternatively, other dimensions may be used.

In one embodiment, the wrist, elbow, and shoulder assemblies 220, 230,and 240 and the plate member 380 of the robotic arm 302 may includecomponents manufactured by KUKA Roboter GmbH of Germany.

The track mount assembly 350 may be coupled to a track 360 and to theplate member 380. The track mount assembly 350 and track 360 facilitatetranslational movement of the patient treatment couch 103 in asubstantially horizontal, linear axis, axis 7 of FIG. 3A. Thesubstantially horizontal, linear axis (x-, y-) is substantiallyperpendicular to the two dimensional vertical plane (z-). Track 360 iscoupled to the floor. In another embodiment, the track 360 may bevertically oriented, for example, vertically mounted to a vertical sideof column 270. The column 270 may be secured or mounted to the floor ofthe treatment room during therapeutic radiation treatment or below thefloor in a pit. In another embodiment, column 270 may be secured ormounted to the ceiling of the treatment room during therapeuticradiation treatment. Alternatively, the track 360 may be verticallymounted to other structures known to those skilled in the art, such as awall, pedestal, block, or base structure.

The abovementioned arrangement of the wrist assembly 220, elbow assembly230, shoulder assembly 240, plate member 380, track mount assembly 350,and track 360 facilitate the positioning of the patient treatment couch103 using six rotational degrees of freedom and one translationalsubstantially horizontal, linear degree of freedom. The six rotationaland one substantially horizontal, linear DOF of the robotic arm 302 ofthe robotic patient positioning assembly 100 may position a patient onthe patient treatment couch 103 in substantially any place in a desiredtreatment area, such as a workspace, within the mechanical range ofmotion of the robotic arm 302. The robotic arm 302 may position thepatient treatment couch 103 to have a tool center position (TCP) inmultiple locations within the workspace or treatment area. The roboticarm 302 may also provide loading/unloading positions for a particularpatient. In one embodiment, the six DOF includes three rotational axesfor translational movements along mutually orthogonal coordinate axes(x-, y-, and z-); and three rotational axes for roll-, pitch-, andyaw-rotational movements about x-, y-, and z-axes, respectively. The onesubstantially horizontal, linear DOF includes a substantial linear axisfor translational movement along a substantially horizontal line in acoordinate axis (x-, and y-) substantially perpendicular to the verticalcoordinate axes (z-).

In one embodiment, the robotic arm 302 includes one or more patienttreatment couch motion actuators for moving the patient treatment couch103, in accordance with directions from the controller 101. A tableinterface module allows the patient treatment couch 103 to interfacewith the sensor system 104, the actuators of the robotic arm 302/102,the controller 101, the therapeutic radiation treatment system 106, andthe user interface unit 105. The electronics module may independentlycheck patient treatment couch positions against a model of surroundingobstructions to ensure that the patient treatment couch 103 does notcollide with obstacles during motion of the robotic patient positioningassembly 100.

As described above, the patient treatment couch 103 is capable of motionin at least five rotational degrees of freedom, namely two translationaldegrees of freedom (x- and y-axes) (axes 2 and 3, respectively, of FIG.2A), three rotational degrees of freedom (yaw-, pitch-, and roll-axes)(axes 6, 5, and 4 of FIG. 2A), and one substantially vertical, lineardegree of freedom (substantially vertical, linear axis) (axis 1 of FIG.2A). Alternatively, the patient treatment couch 103 may be capable ofmotion in all six degrees of freedom, namely three translational degreesof freedom (x-, y-, and z-axes) (axes 3, 2 and 1, respectively, of FIG.3A) plus three rotational degrees of freedom (roll-, pitch- andyaw-rotations) (axes 6, 5, and 4, respectively, of FIG. 3A), and onesubstantially vertical, linear degree of freedom (substantiallyvertical, linear axis) (axis 7 of FIG. 3A). The motion command signals,generated by the controller 101, may control corrective motions of therobotic patient positioning assembly 100 in the various degrees offreedom. In one embodiment, the position of the patient treatment couch103 with respect to the treatment system 106 may be known, so thatcoordinated movements may be effected. In one exemplary embodiment, boththe patient treatment couch 103 and the treatment system 106 can bereferenced to a common (or “room”) coordinate system.

FIG. 3B illustrates one embodiment of patient treatment couch coupled tothe robotic arm of FIG. 3A. Robotic arm 302 is coupled to the mountingplate 211. The robotic arm 302 is coupled to track 360. In thisembodiment, track 360 is mounted to the floor and is encased in a trackencasing 370. In another embodiment, the track 360 may be verticallyoriented, for example, vertically mounted to a vertical side of column270. As previously discussed, the column 270 may be secured or mountedto the floor or ceiling of the treatment room during therapeuticradiation treatment or below the floor in a pit. Alternatively, thetrack 360 may be vertically mounted to other structures known to thoseskilled in the art, such as a wall, pedestal, block, or base structure.The robotic arm 302 of FIG. 3B includes the members and assemblies thatmake up the robotic arm 302 of FIG. 3A, as discussed above, but thesemembers and assemblies are not discussed with respect to FIG. 3B as tonot obscure the discussion of the coupling of the robotic arm 302 andthe patient treatment couch 103.

In FIG. 3B, mounting plate 211 is coupled to the patient treatment couch103. In one embodiment, the mounting plate 211 may be attached to thepatient treatment couch 103 at an off-center position or pivot point. Inone embodiment, the length 315 of the patient treatment couch 103 may beapproximately in a range of forty-eight to one hundred and forty fiveinches (48″-145″). The width 314_of the patient treatment couch 103 maybe approximately in a range of ten inches and forty-five inches(10″-45″). In one exemplary embodiment, length 315 is approximately 78inches and the width 314 is approximately twenty inches (20″).

In one embodiment, the off-center position 317 may be approximately in arange of fifty to seventy-five inches (50″-75″) from one side of thepatient treatment couch 103 (e.g., side that includes the patient headrest) with respect to the length 315 of the patient treatment couch 103.In one exemplary embodiment, the off-center position 317 is fifty inches(50″) from one side of the patient treatment couch 103 with respect tothe length 315 of the patient treatment couch 103. In anotherembodiment, the off-center position 317 is an off-center length distance312 and an off-center width distance 318 from the center position 316 ofthe patient treatment couch 103. In one embodiment, the off-centerlength distance 312 may be approximately in a range of zero to ninetypercent (0-90%) of a distance to one side of the patient treatment couch103 from the center position 316 with respect to the length 316 and theoff-center width distance 318 may be approximately in a range of zero toninety percent (0-90%) of a distance to one side of the patienttreatment couch 103 from the center position 316 with respect to thewidth 314. In an exemplary embodiment, the off-center position 317 isapproximately twenty-five inches (25″) from a center position 316 withrespect to a length 315 of the patient treatment couch 103 andapproximately four inches (4″) from the center position 316 with respectto a width 314 of the patient treatment couch 103. Or in other words,the off-center length distance 312 is twenty-one inches (21″) and theoff-center width distance 318 is four inches (4″). In anotherembodiment, the off-center position 317 may be expressed in terms ofpercentages, for example, the off-center position 317 may be locatedwithin approximately 50-85% with respect to the length 315 of thepatient treatment couch 103 and within approximately 0-50% with respectto the width 314 of the patient treatment couch 103. Alternatively, themounting plate 211 may be coupled to the patient treatment couch 103 inthe center position 216 with respect to the length 215 and the width 214of the patient treatment couch 103.

The patient treatment couch 103 in one embodiment may have a thickness313 approximately in a range of 0.75 inches to 3 inches. In oneexemplary embodiment, the patient treatment couch 103 has a thickness313 of approximately 2.25 inches. In another exemplary embodiment, thepatient treatment couch 103 has a thickness 313 of approximately 2.25inches, a length 315 of approximately 77 inches, and a width 314 ofapproximately 20 inches. As described above in relation to thediscussion of FIG. 2C, the patient treatment 103 may be made ofradiolucent material. In one embodiment, the patient treatment couch 103includes a skin material 256 and a body material 257. In one exemplaryembodiment, the skin material 256 is carbon fiber and the body material257 is foam. Alternatively, other radiolucent material may be used forthe skin and body materials. In one embodiment, the skin material 256includes a skin thickness 258. The skin thickness 258 may beapproximately in a range of 0.02 to 0.12 inches. In one exemplaryembodiment, the skin thickness may be approximately 0.058 inches.

In one embodiment, patient treatment couch 103 coupled to the mountingplate 211 in an off-center position 317 enables support of a patientload up to five hundred pounds within a deflection error 261 ofapproximately zero to five millimeters (0 to 5 mm) of the patienttreatment couch 103. In another embodiment, the thickness 313 of thepatient treatment couch 103 enables support of a patient load up to fivehundred pounds within a deflection error 261 of approximately zero tofive millimeters (0 to 5 mm) of the patient treatment couch 103.Alternatively, both the coupling of the patient treatment couch 103 tothe mounting plate 211 in an off-center position 317 and the thickness313 of the patient treatment couch enables support of a patient load upto five hundred pounds within a deflection error 261 of approximatelyzero to five millimeters (0 to 5 mm) of the patient treatment couch 103.It should be noted that the patient treatment couch 103 and robotic arm302 may support more weight than five hundred pounds. In one embodiment,the patient treatment couch 103 and robotic arm 302 may enable supportof a patient load up to approximately two thousand pounds (2000 lbs) ina static position.

FIGS. 4A and 4B illustrate exemplary positions of the robotic patientpositioning assembly 100 having five rotational degrees of freedom andone substantially vertical, linear degree of freedom together with arobot-based linac system 406. The robotic patient positioning assembly100 of FIGS. 4A and 4B includes a robotic arm 202, patient treatmentcouch 103, mounting plate 211, wrist assembly 220, elbow assembly 230,shoulder assembly 240, track mount assembly 250, track 260, column 270,robot-based linac system 406 having robotic arm 402, and x-ray imagingsources 407 of imaging system 107. In the illustrated embodiments, therobot-based linac system 406 may be the CyberKnife® radiosurgery systemor another robot-based linac system. The robotic patient positioningassembly 100 of FIG. 4A illustrates an exemplary low position orloading/unloading position of the patient treatment couch 103 having aload (e.g., a patient). In one embodiment, this low position may be apre-programmed position for loading/unloading a patient. The lowposition or loading/unloading position may be approximately in a rangeof sixteen to twenty-five inches (16″-25″) from the floor. In thisembodiment, a patient may be loaded to the patient treatment couch 103from a wheelchair. Alternatively, the position may result from the usermanually controlling the robotic arm 202 and patient treatment couch 103by the user interface 105.

The robotic patient positioning assembly 100 of FIG. 4B illustrates anexemplary high or “TREAT” position of the patient treatment couch 103.In this exemplary embodiment, the high or “TREAT” position is higherthan the low position of FIG. 4A for loading/unloading a patient. In oneembodiment, the high position may be a default position before beginningtreatment. This “TREAT” position may be pre-programmed in the controller101 or alternatively, may result from manual control from the user fromthe user interface 105.

In one embodiment, the patient treatment couch 103 may be made of aradiolucent material so that the patient could be imaged through thepatient treatment couch 103. An exemplary imaging system 107 that can beused with the robotic patient positioning assembly 100 and therobot-based linac system 406 includes two x-ray imaging sources 407,power supplies associated with each x-ray imaging source, one or twoimaging detectors 408, and controller 101. The x-ray imaging sources 407may be mounted angularly apart, for example, about 90 degrees apart, andaimed through the treatment target (e.g., tumor within the patient)toward the detector(s) 408. Alternatively, a single large detector maybe used that would be illuminated by each x-ray source. In the singledetector imaging system 107, the two x-ray sources 407 may be positionedapart at an angle less than 90 degrees to keep both images on the singledetector surface.

The detector(s) 408 may be placed below the treatment target, e.g., onthe floor, on the patient treatment couch 103, or underneath the patienttreatment couch 103, and the x-ray imaging sources 407 may be positionedabove the treatment target (e.g. the ceiling of the treatment room), tominimize magnification of the images and therefore the required size ofthe detector(s) 408. In an alternative embodiment, the positions of thex-ray imaging sources 407 and the detector(s) 408 may be reversed, e.g.the x-ray imaging sources 407 below the treatment target and thedetector(s) 408 above the treatment target. In another embodiment, dueto the constrained swing of the gantry of the therapeutic radiationtreatment system 106, and to reduce the magnification effects, thedetector(s) 408 may be arranged in a manner such that they move intoposition for imaging while the gantry may be positioned in a way thatdoes not interfere with the imaging system 107, and then move out of theway during delivery of the therapeutic beam of the therapeutic radiationtreatment system 106.

The detector(s) 408 may generate the image information of the patientand send it to the controller 101. The controller 101 performs all theimaging calculations to determine the patient's position with respect tothe desired treatment position and generate corrections for the variousdegrees of freedom. The corrections could be automatically applied tothe robotic patient positioning assembly 100 to automatically align thepatient, and/or sent to the controller 101 to automatically adjust thepatient's position relative to the therapeutic radiation source 409 ofthe robot-based linac system 406, and/or sent to the user interface unit105 for a user to manually adjust the patient's position relative to thetherapeutic radiation source 409 of the robot-based linac system 406.

As previously mentioned, the robotic patient positioning assembly 100including the controller 101 may know the position of the patienttreatment couch 103 through the sensor system 104 and the position ofthe treatment target through the real time or near real time image data,and also knows the position of the of the linac system and may generatemotion command signals for implementing corrective motions of therobotic patient positioning assembly 100 for aligning the treatmenttarget with respect to the radiation treatment sources of thetherapeutic radiation treatment system 106. In one embodiment using arobot-based linac system 406 for the therapeutic radiation treatmentsystem 106, the corrective motions of the robotic patient positioningassembly 100 may be dynamically coordinated with the motions of thetreatment x-ray source of the therapeutic radiation treatment system 106using the controller 101, in a way as to maximize the workspaceavailable to the robot-based linac system 406. In other words, bydynamically coordinating the motions of the treatment x-ray source ofthe therapeutic radiation treatment system 106 using the controller 101,the available number of treatment targets increases due to the increasednumber of orientations and positions of the patient treatment couch 103and the therapeutic radiation treatment system 106, which are free ofobstructions, for example, by detectors 408 and/or x-ray imaging sources407 (as shown in FIGS. 4A & 4B). In this embodiment, therobot-implemented movements of the treatment x-ray source of therobot-based linac system 406 are complemented by the corrective motionsof the robotic patient positioning assembly 100, so that the relativemotion between the treatment x-ray source and the patient treatmentcouch 103 ensures the delivery of the desired radiation patternthroughout the target region.

In one embodiment, the combination of the motions of the patienttreatment couch 103 and the motions of the x-ray linac of thetherapeutic radiation treatment system 106, are dynamically coordinatedand controlled, so as to maximize the workspace available to thetherapeutic radiation treatment system 106.

The robotic arm 202 may position the patient treatment couch 103 to havea tool center position (TCP) or treatment target in multiple locationswithin the workspace or treatment area. The robotic arm of therobot-based linac system 406 may also position the iso-center of thelinac therapeutic radiation source 409 in multiple locations within theworkspace or treatment area. The workspace or treatment area, however,may be limited by positioning restrictions, for example, obstructionscaused by a possible collisions between either the patient treatmentcouch 103, the therapeutic radiation source 409, or their correspondingrobotic arms with components of the therapeutic radiation treatmentsystem 106, imaging system 107, and/or robotic arm 102 or obstruction ofthe radiation beam of the therapeutic radiation source 409 of therobot-based linac system 406 with any of these above mentionedcomponents. For example, the x-ray imaging sources 407 may prevent thetherapeutic radiation source 409 of the robot-based linac system 406from being positioned where the x-ray imaging sources 407 are mountedbecause positioning it there would result in a possible collision (e.g.,collision obstructions). Similarly, the therapeutic radiation source 409of the robot-based linac system 406 may not be positioned under thepatient treatment couch 103 due to the placement of the detectors 408(e.g., collision obstructions). Another example of a positioningrestriction is obstructions of the radiation beam from the therapeuticradiation source 409 due to other components, for example, the detectors408 and/or x-ray imaging sources 407 (e.g., beam obstructions).

In one embodiment, the controller 101 may be configured to dynamicallymove in combination the patient treatment couch along five rotationaldegrees of freedom and one substantially vertical, linear degree offreedom using the robotic arm, and the robot-based linac system along atleast five degrees of freedom using a robotic arm of the robot-basedlinac system to dynamically coordinate orientation and position of thepatient treatment couch 103 and a therapeutic radiation source 409 ofthe robot-based linac system 406. The dynamic coordination of movementbetween the patient treatment couch and the therapeutic radiation sourcemay increase a number of treatment targets within a mechanical range ofmotion of the robotic arm.

The controller 101 may be configured to position the patient treatmentcouch 103 and the robot-based linac system to create a treatment targetin a previously obstructed location caused by a positioning restrictionwithin a mechanical range of motion of the robotic arm and therobot-based linac system. In one embodiment, the previously obstructedlocation may be caused by an obstruction of a possible collision, forexample, between either the patient treatment couch 103, therapeuticradiation source 409, or their corresponding robotic arms with therobotic arm 202, the patient treatment couch 103, the therapeuticradiation source 409, x-ray imaging sources 407, detectors 408, and/orother components of the robot-based linac system 406. Alternatively, thepreviously obstructed location may be caused by an obstruction of theradiation beam of the therapeutic radiation source 409 with the roboticarm 202, the patient treatment couch 103, the therapeutic radiationsource 409, x-ray imaging sources 407, detectors 408, and/or othercomponents of the robot-based linac system 406.

In one embodiment, an anti-collision model may be embedded in thecontroller 101 to ensure that the patient is not positioned in anorientation and/or position that might cause a possible collisionbetween the patient treatment couch 103 including the patient's body andthe linac gantry or other moving parts of the robot-based linac system406.

FIG. 4C illustrates a top-down view of a total usable surface area atherapeutic radiation source having a robotic arm of the robot-basedradiosurgery system mounted to a first side of a conventional treatmenttable. In this embodiment, therapeutic radiation source 409 is coupledto a robot-based linac system 406, as described above with respect toFIGS. 4A and 4B. The robot-based linac system 406 is mounted to thefloor on one side of a conventional treatment table 401. Conventionaltreatment couch 401 is a floor mounted treatment table. As describedabove, the therapeutic radiation source 409 may be positioned using therobotic arm 402 of the linac system 406 (e.g., articulated robotic arm)in a three-dimensional workspace within the mechanical range of motionof the robotic arm 402. The therapeutic radiation source 409 may bepositioned to be a certain distance from the treatment target within thepatient on the conventional treatment table 401. The certain distancebetween the radiation source 409 and the treatment target of the patientis the source axis distance (SAD). Since the robot-based radiationsource 409 may be positioned and oriented within the 3-D workspace usingthe robotic arm 402 of the robot-based linac system 406, the radiationsource 409 has a total usable surface area 404, which may be dependantupon the SAD. In one embodiment, if the SAD is a fixed number, the totalusable surface area 404 would have approximate spherical shape.Alternatively, other usable surface areas may be used of differentshapes that have been obtained by varying the SAD. The total usablesurface area 404 may represent the positions or nodes in which theradiation source 409 (e.g., x-ray linac) may be positioned to emittherapeutic radiation to the treatment target within the patient. Thetotal usable surface area 404 may be limited by positioning restrictionsas described above.

In one embodiment, the positioning restriction may be caused by atreatment table or couch. In one exemplary embodiment, the positionrestriction may cause an unreachable surface area 404 due to theobstruction of the floor mounted conventional treatment table and thefloor mounted robot-based linac system 406. Alternatively, otherobstructions may cause the radiation source 409 to have unreachablesurface areas. In one embodiment, the unreachable surface area 404 maybe caused by the robot-based linac system 406 being mounted to one sideof the conventional treatment table 401, as illustrated in FIG. 4C. FIG.4C includes a two-dimensional circular shape of the total usable surfacearea 404 and the unreachable surface area 405. It should be noted thatalthough represented as a two-dimensional circular shape in FIG. 4C, thetotal usable surface area 404 may be the surface area of an approximatespherical shape. Alternatively, other usable surface areas may be usedof different shapes that have been obtained by varying the SAD.

It should be noted that the unreachable area 404 can not be cured bymerely mounting the robotic arm of the robot-based linac system 406 onthe opposite side of the conventional treatment table 401, asillustrated in FIG. 4D. FIG. 4D illustrates a top-down view of the totalusable surface area 404 of the therapeutic radiation source 409 havingthe robotic arm of the robot-based linac system 406 mounted to a secondside of the conventional treatment table 401. In this embodiment, theunreachable surface area 405 remains due to the obstruction of theconventional treatment table 401 and the robotic arm of the robot-basedlinac system 406. In other words, merely mounting the robot-basedradiosurgery system on another side does not overcome the positioningrestriction due to the obstruction causing the unreachable area 405.

FIG. 4E illustrates a top-down view of a total usable surface area ofone embodiment of a therapeutic radiation source and a patient treatmentcouch. In this embodiment, therapeutic radiation source 409 is coupledto a robot-based linear accelerator system 406 as described above withrespect to FIGS. 4A and 4B. In this embodiment, therapeutic radiationsource 409 is coupled to a robot-based linac system 406, as describedabove with respect to FIGS. 4A and 4B. The robot-based linac system 406is mounted to the floor on one side of patient treatment couch 103 inposition 403 a. Alternatively, the robot-based linac system 406 may bemounted to the floor on the opposite side of patient treatment couch103. Patient treatment couch 103 is coupled to robotic arm 202. Thedetails of patient treatment couch 103 and robotic arm 202 have beendescribed herein, and are not repeated here as to not obscure thediscussion of increasing the total usable surface area 404. In thisembodiment, patient treatment couch 103 and robotic arm 202 arevertically mounted. Alternatively, a floor or ceiling mounted roboticarm may be used. As described above, the therapeutic radiation source409 may be positioned using the robotic arm 402 of the linac system 406(e.g., articulated robotic arm) in a three-dimensional workspace withinthe mechanical range of motion of the robotic arm 402. The therapeuticradiation source 409 may be positioned to be a certain distance, theSAD, from the treatment target of the patient on the patient treatmentcouch 103. Since the robot-based radiation source 409 may be positionedand oriented within the 3-D workspace using the robotic arm 402 of therobot-based linac system 406, the radiation source 409 has a totalusable surface area 404, which may be dependant upon the SAD. In oneembodiment, if the SAD is a fixed number, the total usable surface area404 would have approximate spherical shape. Alternatively, other usablesurface areas may be used of different shapes that have been obtained byvarying the SAD.

The total usable surface area 404 may represent the positions or nodesin which the radiation source 409 (e.g., x-ray linac) may be positionedto emit therapeutic radiation to the treatment target of the patient.The total usable surface area 404 may be limited by positioningrestrictions as described above.

As described above, the positioning restriction may be caused bytreatment table or couch. In this embodiment, however, the patienttreatment couch 103 and the robotic arm 202 may be positioned toeliminate the unreachable area 405 as described and illustrated withrespect to FIGS. 4C and 4D. FIG. 4E illustrates the new position of thepatient treatment couch 103 as patient treatment couch 403 b. In thisembodiment, the position of the patient treatment couch 103 is shiftedfrom position 403 a to 403 b. In other words, the patient treatmentcouch 103 coupled to the robotic arm 202 may increase the total usablesurface area 404 that the therapeutic radiation source 409 may bepositioned for emitting therapeutic radiation to the treatment target ofthe patient. Alternatively, other movements may be used to eliminate theunreachable surface area and to increase the total usable surface area404 of FIG. 4E.

FIG. 4E includes a two-dimensional circular shape of the total usablesurface area 404. It should be noted that although represented as atwo-dimensional circular shape in FIG. 4C, the total usable surface area404 may be the surface area of an approximate spherical shape.Alternatively, other usable surface areas may be used of differentshapes that have been obtained by varying the SAD.

In another embodiment, the obstruction may be caused by the ground;thus, when using a conventional treatment table 401, the obstructioncreates an unreachable surface area on a bottom portion of anapproximately spherical usable area. Using a vertically mounted roboticarm 202 and patient treatment couch 103 the patient treatment couch 103may be raised up from the floor from a first position to a second higherposition, eliminating the unreachable surface area and increasing thetotal usable surface area. Alternatively, other unreachable surfaceareas may be overcome by coordinating the movement of the robotic arm202 and the patient treatment couch 103, such as, for example,obstructions due to the detectors 408, and x-ray imaging sources 407.

FIG. 4F illustrates an alternative embodiment of a robot arm mounting toa couch. In this embodiment, robotic arm 202 is mounted to patienttreatment couch 103 on an extension mounting area 491 of the couch. Itshould be noted that the extension mounting area 491 may also bedisposed at another location along the periphery of the patienttreatment other than as shown in FIG. 4F. Alternatively, if the patienttreatment couch 103 is sufficient thickness 213 (illustrated in FIG. 2B)in the mounting region, the robot arm 202 may be mounted directly to anedge side 496 of the couch without the use of extension mounting area491. The mounting of robotic arm 202 on extension mounting area 491 (or,alternatively, on to edge side 496) may allow for the robotic arm to beout of the imaging field of view for all supported treatment positions(a 90 degree orientation position example is described below in relationto FIG. 4G). As previously discussed, in one embodiment, the patienttreatment couch 103 is constructed from radiolucent material. However,the robotic arm 202 may not be constructed from such radiolucentmaterial. Accordingly, the robotic arm 202 may not be imaged through andcause an imaging obstruction when it moves the patient treatment couch103 in certain positions with respect to the imaging system.

FIG. 4G illustrates a side and top view of one embodiment of the roboticarm mounting of to the couch of FIG. 4F in relation to an imagingsystem. As discussed above in relation to FIGS. 4A and 4B, the imagingsystem used with the robotic patient positioning assembly 100 and therobot-based linac system 406 may include two x-ray imaging sources(Source A and Source B) 407 and two imaging detectors (Detector A andDetector B) 408. In the orientation of the patient treatment couch 103with respect to the detectors 408 illustrated in FIGS. 4A and 4B, therobotic arm 202 may not interfere or obstruct the imaging field of viewof the detectors. However, when the robotic arm 202 orients the patienttreatment couch 103 at approximately 90 degrees with respect to theorientation of FIGS. 4A and 4B, the robot arm 202 may cause an imagingobstruction in certain positions when mounted as shown in FIGS. 4A and4B. FIG. 4G illustrates the patient treatment couch oriented at a 90degree position with respect to the configuration of the couch anddetectors illustrated in FIGS. 4A and 4B. For example, in this 90 degreeorientation (and at other orientations), by using an extension mountingarea 491 (or edge side 496 mounting) for the robot arm 202, the roboticarm 202 may be maintained substantially outside the imaging field 495 ofthe imaging system (e.g., x-ray imaging sources 407 and imagingdetectors 408).

FIG. 5 illustrates one embodiment of a schematic diagram of a handhelduser interface unit. The user interface unit 500 may affect computercontrol of the at least five rotational DOF and one substantiallyvertical, linear DOF of the robot-controlled patient treatment couch103. In an exemplary embodiment, the user interface unit 500 includes: abus interface for connecting the patient treatment couch 103 to thetreatment system primary workstation including the controller 101,sensor system 104, imaging system 107, robotic arm 102, the therapeuticradiation treatment system 106; and at least one user interface unit105, such as user interface unit 500 for allowing the user to interfacewith the controller 101 to interactively control the motion of therobotic patient positioning assembly 100; and a hardware interface tothe treatment system E-stop (emergency stop) circuitry. The businterface may be an Ethernet bus interface that can be connected to thetreatment system primary workstation. The hardware interface to theE-stop circuitry may disable computer-controlled motions of the roboticpatient positioning assembly 100 when any E-stop is engaged.

The E-stop mechanism may be operable to stop computer-controlled motionof the robotic patient positioning assembly 100. In one embodiment, the“System E-stop” may be an emergency lockout mechanism, capable ofshutting down any and all radiation, and any and all motion. In otherwords, the “System E-stop” may shut down at least the following: 1)generation of therapeutic x-ray beams by the treatment x-ray source ofthe therapeutic radiation treatment system 106; 2) any motion of thetreatment x-ray source and/or the robotic arm of the therapeuticradiation treatment system 106; 3) any motion of the robotic arm 102 andthe patient treatment couch 103; and 4) the imaging system 107.

The user interface unit 500 may allow the user or operator tointeractively participate in controlling the motion of the robotic arm102 and the patient treatment couch 103, by implementing one or moreuser-selectable functions. In one embodiment, the user interface unit500 may be a remote control unit. Alternatively, the user interface unitmay be a graphical user interface unit, as described below. Theseuser-selectable functions may include, but are not limited to, thefollowing: 1) a function that allows the user to power on the patienttreatment couch 103, so that the acquisition of the position of thepatient treatment couch 103 can be initiated; 2) a function that allowsthe user to activate the x-ray imaging system 107, so that theacquisition of real time or near real time images of the target can beinitiated; 3) a function for allowing the user to move the patienttreatment couch 103 to one or more pre-programmed loading positions,which facilitates the loading of the patient onto the patient treatmentcouch 103 in a desired manner; 4) a function for allowing the user tomove the patient treatment couch 103 to a pre-programmed “TREAT”position, which may be the default treatment position; 5) a function fordisplaying to the user the translations and rotations corresponding tothe patient treatment couch 103 corrective motions needed to adjust thetarget position, in accordance with the information from the real timeor near real time images; 6) a function for allowing the user to comparethe translations and rotations with respective pre-specified limits foreach translation and rotation; 7) a function for allowing the user tomodify one or more of the pre-specified limits; and 8) a function forallowing the user to verify that the translations and rotations fallbelow the pre-specified limits, and thereupon activate the treatmentx-ray source of the therapeutic radiation treatment system 106 toinitiate treatment delivery.

In one exemplary embodiment, the user interface unit 500 may be ahandheld remote control unit (e.g., handheld pendant) that provides auser with remote control capabilities for remote control of the motionof the robotic arm 102 and patient treatment couch 103. User interfaceunit 500 of FIG. 5 may be a handheld pendant, and may include a numberof button icons respectively associated with these user-selectablefunctions. The handheld remote control unit 500 may provide controls tomanually adjust the patient's position, and status indicators related tothe motions of the robotic patient positioning assembly 100.

In the illustrated embodiment, the handheld remote control unit 500includes motion switches: six sets of axes motion control switches510A-510F, three loading position switches 520A, 520B, and 520C, and atreat switch 530. The axes motion control switches may providebi-directional manual control of each degree of freedom via apushbutton. The axes motion control switches may cause movement of thedesired axes (three rotational axes: left/right (510A),posterior/anterior (510B), inferior (towards the feet)/superior (towardsthe head) (510C); three rotational axes: roll left/right (510D); headdown/up (510E); head left/right (510F)) in the desired direction, aslong as the switch is held down and motion is disabled. The loadingswitches 520A, 520B, and 520C may each initiate a programmed motion, ifmotion is enabled, that causes the patient treatment couch 103 toautomatically move to the fully retracted, fully lowered loadingposition without any further operator action. The controller 101 mayhave one or more pre-programmed loading positions, and alternatively, auser may manually set a loading position for a patient through thehandheld user interface unit 500 or a computer interface 600 illustratedin FIG. 6. The controller 101 may store the loading position for aparticular patient for future treatment. The treat switch 530 mayinitiate a programmed motion, if motion is enabled, that causes thepatient treatment couch 103 to move to a position defined by thecontroller 101 and previously downloaded to the patient treatment couch103.

The remote control unit 500 may also include a pair of motion enableswitches 550. Depressing one or both switches may enable all motionswitches (axes motion control, loading positions, and treat), andoverrides the System E-stop, if present, although it may not overrideany table E-stop switches. Releasing one or both of the enable switcheswhile a programmed motion is occurring may cause that motion to stop.

The remote control unit 500 may also include a pair of status indicators540 and 542, which may be light emitting diodes (LEDs) that provide anindication of whether motions are enabled and being accepted. In theillustrated embodiment, the E-stop LED 540 may be yellow when SystemE-stop is asserted, green when overridden by enable switches, and offwhen no System E-stop is asserted. The MOVE LED 542 may be greenwhenever a switch is pushed and motion is enabled, flashing green when aprogrammed movement is occurring, and yellow when the table E-stop isengaged.

The remote control unit 500 may also include a GoTo switch (not shown),allowing the user to access stored locations. The remote control unit500 may also include display capabilities (not shown), for example todisplay to the user the translations and rotations, or to displayinformational messages to the user. The remote control unit 500 may alsoinclude absolute and relative position display/input modes (not shown).In another embodiment, the remote control unit 500 may also include aswitch for activating the sensor system 104 to initiate detecting theposition of the patient treatment couch 103.

One or more user interface screens on the user control console of theprimary workstation of the CyberKnife® radiosurgery system, may allowthe user to inspect, initiate, and interactively control the motion ofthe robotic patient positioning assembly 100 for positioning thepatient. FIG. 6 illustrates an exemplary embodiment of a user interfacescreen 600, launched into a treatment delivery screen 640 of the primaryworkstation. In the illustrated embodiment, the user interface screen600 may provide to the user an integrated patient treatment couchposition display, and patient treatment couch motion controlcapabilities. The user interface screen 600 provides sub-options toadjust translations only, or rotations only or all degrees of freedomavailable together.

In one embodiment, the user interface screen 600 includes button iconsthat allow the user to activate the sensor system 104 to detect theposition of the patient treatment couch 103.

In the illustrated embodiment, an ALIGN COUCH button in the treatmentdelivery screen 640 may launch the user interface screen 600. The userinterface screen 600 may include a number of fields, with differentfunctions. These fields may include translation and rotation fields,which are initially filled with the corrective motions of the roboticpatient positioning assembly 100 returned by the TLS unit of thecontroller 101. If no valid patient treatment couch corrective motionsare available, these fields are left blank. The translation and rotationfields may be editable.

In the illustrated embodiment, the user interface screen 600 includes aMOVE button 610, an “AUTO ALIGN” button 320, and a “CANCEL” button 630.The “MOVE” button 610 moves the patient treatment couch 103 by theamount of translations and rotations indicated. If the “Apply rotation”field is unchecked, the patient treatment couch 103 may be moved only inrotational axes. The “AUTO ALIGN” button 620 initially moves the patienttreatment couch 103 by the amount of translations and rotationsindicated, and proceeds to acquire images through the imaging system 107and correct patient treatment couch 103 positions automatically untilpre-specified “Auto align limits” are satisfied. This may mean that thetranslations and rotations are below the pre-specified limits, or thenumber of images indicated is taken. The “Auto align limits” fields arefilled in from a system configuration file, but can be edited. The“CANCEL” button 630 will return to the Patient Alignment interface.

In one embodiment, the user interface screen 600 includes button iconsthat allow the user to adjust imaging parameters, such as the intensity,energy, and duration of the x-rays in the imaging beams generated by theimaging system 107; the number of real time or near real time images tobe acquired; the selection and de-selection of fiducials; and rigid bodyparameters.

FIG. 7 illustrates a one embodiment of a method for positioning apatient treatment couch using a robotic arm. The method may includeproviding a patient treatment couch 103 coupled to a robotic arm 102,step 701, and moving the patient treatment couch 103 along fiverotational degrees of freedom and one substantially vertical, lineardegree of freedom using a robotic arm 102, step 702. In one embodiment,the five rotational degrees of freedom include two horizontal rotationalaxes (Axes 3, and 2 of FIG. 2A) (e.g., x-, y-axes) and three rotationalaxes including a yaw axis, a pitch axis, and a roll axis (Axes 6, 5, and4 of FIG. 2A), and the one substantially vertical, linear degree offreedom includes a substantial linear axis for translational movement ofthe patient treatment couch along a substantially vertical line in acoordinate axis (e.g., z-axis) substantially perpendicular to the twohorizontal coordinate axes (e.g., x-, and y-axes).

In another embodiment, the method for positioning a patient treatmentcouch 103 using a robotic arm 102 may include providing a patienttreatment couch 103 coupled to a robotic arm 102, and moving the patienttreatment couch 103 along six rotational degrees of freedom and onesubstantially vertical, linear degree of freedom using a robotic arm102. In one embodiment, the six rotational degrees of freedom includethree rotational axes (Axes 3, 2, and 1 of FIG. 3A) (e.g., x-, y-, & z-)and three rotational axes including a yaw axis, a pitch axis, and a rollaxis (Axes 6, 5, and 4 of FIG. 3A), and the one substantially vertical,linear degree of freedom includes a substantial linear axis fortranslational movement of the patient treatment couch along asubstantially vertical line in a coordinate axis (e.g., z-axis)substantially perpendicular to the two horizontal coordinate axes (e.g.,x-, and y-axes).

In one embodiment, the method may include sustaining a load on thepatient treatment couch up to five hundred pounds (500 lbs) within adeflection error 261 of approximately zero to five millimeters (0 to 5mm). Alternatively, the patient load on the patient treatment couch maybe up to two thousand pounds (2000 lbs) in a static position.

The method may further include moving the patient treatment couch alonga single one of the rotational axes and the rotational axes withoutmoving the patient treatment couch along a different one said axisthroughout an entire range of motion of the patient treatment couch. Themethod may also include providing a controller for moving the roboticarm and patient treatment couch along five or six rotational degrees offreedom and one substantially vertical, linear degree of freedom. Themethod may also include providing a user interface unit coupled to thecontroller for manually moving the robotic arm and patient treatmentcouch along at least one of five and six rotational degrees of freedomand one substantially vertical, linear degree of freedom.

In one embodiment, moving the patient treatment couch along fiverotational degrees of freedom and one substantially vertical, lineardegree of freedom using the robotic arm includes rotating the patienttreatment couch along the yaw-axis using a tool-yaw joint of the roboticarm, rotating the patient treatment couch along the pitch-axis using atool-pitch joint of the robotic arm, rotating the patient treatmentcouch along the roll-axis using a tool-roll joint of the robotic arm,rotating the patient treatment couch along the two horizontal rotationalaxes using a elbow joint and a shoulder joint, and translating thepatient treatment couch along a substantially vertical, linear axisusing a track and track mount assembly perpendicular to the twohorizontal rotational axes. In another embodiment, moving the patienttreatment couch further includes rotating the patient treatment couchalong an additional translational axis using an additional shoulderjoint, totaling six rotational degrees of freedom and one substantiallyvertical, linear DOF. The six DOF may include three rotational axes fortranslational movements along mutually orthogonal x-, y-, andz-coordinate axes; and three rotational axes for roll-, pitch-, andyaw-rotational movements about x-, y-, and z-axes, respectively. The onesubstantially vertical, linear DOF may include a substantial linear axisfor translation along a substantially vertical line in a z-coordinateaxis perpendicular to the horizontal, x-, and y-coordinate axes.

FIG. 8 illustrates another embodiment of a method for positioning apatient treatment couch using a robotic arm and a robot-based linacsystem 406. The method may include providing a patient treatment couchcoupled to a first robotic arm, step 801; providing a robot-basedtherapeutic radiation treatment system using a second robotic arm, step802; moving the patient treatment couch along five rotational degrees offreedom and one substantially vertical, linear degree of freedom usingthe first robotic arm, step 803; and moving the robot-based linac systemalong at least five degrees of freedom using the second robotic arm ofthe robot-based therapeutic radiation treatment system, step 804. Inanother embodiment, the method may further include providing acontroller coupled to the robot-based therapeutic radiation treatmentsystem and the robotic arm.

In one embodiment, moving the patient treatment couch and therobot-based linac system may include dynamically coordinating anorientation and position of the patient treatment couch and atherapeutic radiation source of the robot-based linac system using thecontroller. Dynamically coordinating the orientation and position of thepatient treatment couch and the therapeutic radiation source mayincrease a number of treatment targets within a mechanical range ofmotion of the robotic arm. In another embodiment, moving the patienttreatment couch and the robot-based linac system includes aligning atherapeutic radiation source of the robot-based linac system with atreatment target within a patient disposed on the patient treatmentcouch. In another embodiment, moving the patient treatment couch and therobot-based linac system further includes positioning the patienttreatment couch and the therapeutic radiation source to create atreatment target in a previously obstructed location within a mechanicalrange of motion of the robotic arm and the robot-based linac system.

In one embodiment, the previously obstructed location may be caused byan obstruction of a possible collision, for example, between either thepatient treatment couch 103, therapeutic radiation source 409, or theircorresponding robotic arms with the robotic arm 202, the patienttreatment couch 103, the therapeutic radiation source 409, x-ray imagingsources 407, detectors 408, and/or other components of the robot-basedlinac system 406. Alternatively, the previously obstructed location maybe caused by an obstruction of the radiation beam of the therapeuticradiation source 409 with the robotic arm 202, the patient treatmentcouch 103, the therapeutic radiation source 409, x-ray imaging sources407, detectors 408, and/or other components of the robot-based linacsystem 406.

In operation, an approximate treatment location for the patient may becomputed, as part of the treatment planning process. When the treatmentplan is loaded into the controller 101, the approximate treatmentlocation may be downloaded into the patient treatment couch 103. Theoperator positions the patient on the patient treatment couch 103, andapplies any restraining devices. The operator then presses the “TREAT”button in the handheld user interface unit 500 (shown in FIG. 5), andthe patient treatment couch 103 automatically moves to bring all of itsdegrees of freedom to the stored positions. Alternatively, the “Treat”command could also be issued from the user interface screen 600. Thenumber of axes to move simultaneously may be limited by design to ensurethat power demands are not excessive and that the patient is comfortablewith the number of simultaneous motions taking place.

The operator then exits the treatment room and using the user interfacescreen 600 (shown in FIG. 6) on the workstation or dedicated controlpanel, may command the system to align the patient to within desiredtolerances. The user interface screen 600 may allow the user to enterparameters such as the maximum number of real time or near real timeimages to take during the alignment process, and the desired tolerancesfor position and orientation. The user interface screen 600 also mayallow the errors associated with each image to be displayed.

After obtaining a satisfactory alignment, the therapeutic radiationtreatment system 106 may be commanded to begin treatment. As part of thetreatment, real time or near real time images may be obtainedperiodically by the imaging system 107, to check whether the patientmoves during the treatment. If the patient does move, the treatmentdelivery can be paused automatically or manually by the operator, andthe patient can be realigned, by effecting appropriate correctivemotions of the robotic patient positioning assembly 100. At theconclusion of the treatment, the operator reenters the treatment roomand uses the “Load Position” buttons on the handheld user interface unit500 to return the patient treatment couch 103 to the loading/unloadingposition for patient unloading. Alternatively, the system may issue thecommand to return to the original loading position from the userinterface screen 600.

In one embodiment, components of the robotic arm 202 or robotic arm 302may include touch-sensing material on the components' exterior. Inanother embodiment, the exterior of the components may be coated withcontact foam. Alternatively, other materials may be used to preventcomponents of the robotic arm 202 or of robotic arm 302 from crushing orknocking over the operator. Specific details regarding the touch-sensingmaterial and contact foam that are known to those of ordinary skill inthe art have not been included as to not obscure the discussionregarding coating the exterior of the robotic arms 202 and 302 withmaterial to prevent the operator from being knocked over or crushed bythe robotic arm.

Following is a more detailed description of another embodiment ofoperation of the robotic patient positioning assembly described above.

The first stage is the initial patient set-up stage. During this stage,the treatment planning files are downloaded, prior to patient entry intothe treatment room. During the download of treatment files, thetreatment position of the patient treatment couch 103 may be downloadedinto the controller 101. The treatment position of the patient treatmentcouch 103 may be one of: a) a default patient treatment couch positionfor the beam path set selected; and b) a treatment position for thepatient, the last time the same plan was used. Before the patient walksinto the treatment room, one of the loading position buttons on thehandheld remote control unit 500 may be pressed, so as to position thepatient treatment couch 103 in a pre-defined comfortable position forthe patient to get onto the patient treatment couch 103. The patient maybe then immobilized, for example using a thermoplastic mask and or otherimmobilization devices.

The “TREAT” button on the handheld remote control unit 500 may be usedto position the patient treatment couch 103 to the nominal treatmentposition. For head or body treatments, or if this is a second orsubsequent treatments for the patient with the same plan, the nominaltreatment position may be adequate for further automatic positioning,and the operator can proceed to the user control console for automaticpositioning of the patient. Otherwise, the patient treatment couch 103may be further manually adjusted, using the handheld remote control unit500, so that the anatomical target region of interest may be within theimaging field of view. The operator then proceeds to the user interfacescreen 600, for automatic positioning of the patient.

The next stage may be the initial image acquisition stage. During thisstage, the operator may acquire images, using the ACQUIRE button on thepatient alignment screen in the user interface screen 600 (shown in FIG.6). If necessary, imaging parameters may need to be adjusted. Someexamples of these parameters are: x-ray parameters; de-selection offiducials that may have migrated or otherwise difficult to track; andadjustment of rigid body parameters.

The next stage may be the one-time patient treatment couch alignmentstage. The user selects the “AUTO COUCH” button on the patient alignmentscreen. This brings up a Couch Adjustment interface screen of userinterface screen 600, which contains the initial corrections obtainedfrom the TLS unit of the controller 101. The initial corrections fromTLS may be editable. The “MOVE” button moves the patient treatment couch103 by the amount of corrections indicated in the window. The option todisable rotation corrections may also be available. The “AUTO ALIGN”button may perform the first correction, and proceeds to complete theautomatic alignment.

The next stage may be the automatic patient treatment couch alignmentstage. The “AUTO ALIGN” button in the Couch Adjustment interface screenmay perform the automatic alignment. Auto Align may start by making theinitial correction in the Couch Adjustment interface, and proceeds totake additional images and perform the correction from the image, untilone of the following conditions are met: the desired number of images inthe Auto Alignment phase are acquired, and/or the residual correctionsfall below the limits specified in the Auto Alignment interface.

The next stage may be the patient re-alignment stage. Patientre-alignment may be entered whenever the system encounters a recoverableerror (including operator pause), and the system is resumed from thisstate. Patient re-alignment may be handled the same way as patientalignment. In other words, after the initial acquisition, furtheradjustments can be done automatically using the “AUTO ALIGN” button inthe Couch Adjustment interface.

The final stage may be the treatment delivery stage. Treatment deliverymay be initiated when the corrective motions for the patient treatmentcouch 103 fall below pre-specified limits for translations and rotationsof the robotic arm 102 and patient treatment couch 103. The correctivemotions downloaded to the controller 101 of the robotic patientpositioning assembly 100 may include translations and the specified setof rotations. The robot may move to the nominal position for the node,correct by the specified translation and rotation, and then enable thex-ray beam generator of the therapeutic radiation treatment system 106.At the end of dose delivery for the node, the robot of the therapeuticradiation treatment system 106 may proceed to the next node in thisnominal position.

The controller 101 may include software for error detection, reporting,and correction. In one embodiment, the error handling software includes“operator pause” functionality. This functionality allows the user tostop image acquisition, if one is in progress, and return to a targetalignment or realignment mode. The user may also stop the motion of therobotic patient positioning assembly 100, if one is in progress, andreturn to the target alignment/realignment mode. The user may also stopsubsequent image acquisitions and motions of the robotic patientpositioning assembly 100, if the “auto alignment” mode is in progress.

In one embodiment, the error handling software also includes afunctionality for handling TLS (target locating system) errors.Appropriate TLS errors, such as soft algorithm errors, and/or E-stop forhardware errors, are reported. Upon acknowledgement of the error, thecontroller 101 may return to the alignment or re-alignment state. Theuser may stop subsequent image acquisitions and motions of the roboticpatient positioning assembly 100, if “auto alignment” is in progress.During the initial alignment, the “patient out of bounds” error may bedisabled, but the “TREAT” button may be disabled until the patient iswithin bounds.

In one embodiment, the error handling software includes functionalityfor handling table interface errors. Table interface errors such ascommunication errors are handled as soft errors, which require useracknowledgment, but do not engage an E-stop. In one embodiment, theerror handling software may include functionality for handling E-stops.In this embodiment, an E-stop stops computer-controlled motion of therobotic patient positioning assembly 100, using a dual redundantmechanism. The controller software stops generating any further motioncommand signals. The patient treatment couch controller hardware may bedisabled from patient treatment couch movement when an E-stop isengaged. Even when the E-stop is engaged, the patient treatment couchmay be capable of moving using the handheld user interface unit 500. Onresumption from pause or a recoverable E-stop, the E-stop may be clearedby system reset from the operator console, which then goes into apatient re-alignment state. At this stage, the user can use auto-alignto refine the patient position. The “RESUME” button on the patientre-alignment screen enables resumption of treatment delivery.

In one embodiment of positioning a patient location and orientationduring medical operations includes positioning a patient treatment couch103 along two horizontal rotational axes (x-, y-)(Axes 2 and 3 of FIG.2A) and three rotational axes (yaw, pitch, and roll)(Axes 6, 5, and 4 ofFIG. 2A); and positioning the patient treatment couch 103 along onesubstantially vertical, linear axis (z-)(Axes 1 of FIG. 2A).

In another embodiment of positioning a patient location and orientationduring medical operations includes positioning a patient treatment couch103 along three rotational axes (x-, y-, z-)(Axes 3, 2, and 1 of FIG.3A), and three rotational axes (yaw, pitch, and roll)(Axes 6, 5, and 4of FIG. 3A); and positioning the patient treatment couch 103 along onesubstantially vertical, linear axis (z-)(Axes 7 of FIG. 3A).

In one embodiment, the patient treatment couch 103 may be provided withan at least two directions loading mechanism, which, in operation, canload or unload the patient in horizontal manners and vertical manners.The robotic patient positioning assembly 100 includes the patienttreatment couch 103, which, in a vertical loading manner, may bepositioned oblique to the horizontal plane, for example at approximatelyseventy degrees (70° with respect to the horizontal plane. After thepatient is secured on the patient treatment couch 103, the patienttreatment couch 103 may position the patient to the treatment positionwithin the workspace. In one embodiment, the top surface of the patienttreatment couch 103 may be provided with a patient specific mold, whichmay be customized to fit the body curve of the patient. In anotherembodiment, one end of the patient treatment couch 103 may be providedwith a footplate for supporting the patient's feet in vertical loadingmanners. In another embodiment, the patient treatment couch 103 may beprovided with a chair-like supporting device, and the patient treatmentcouch 103 may be adapted to provide a sitting position for loadingand/or unloading, and/or for treating the patient.

Alternatively, the patient treatment couch 103 may also provideloading/unloading positions as shown in FIG. 4A, sittingloading/unloading positions, and other loading/unloading positions thatare set for the convenience of particular patients.

It should be noted that more rotatable and/or slidable sections, forexample, an additional arm, may be added to the robotic patientpositioning assembly 100 to obtain more flexibility and a greater reachof the patient treatment couch 103. Alternatively, the robotic patientpositioning assembly 100 can include fewer sections than the roboticpatient positioning assembly 100, for example, including only an elbowassembly instead of both the elbow assembly and shoulder assembly. Thetranslational and rotational movements of the robotic patientpositioning assembly 100 may be controlled manually and/or automaticallyby the computer controller 101.

In the foregoing specification, embodiments of the invention have beendescribed with reference to specific exemplary embodiments thereof. Itwill, however, be evident that various modifications and changes may bemade thereto without departing from the broader spirit and scope of thepresent embodiments as set forth in the claims. The specification anddrawings are, accordingly, to be regarded in an illustrative rather thana restrictive sense.

1. An apparatus comprising: a patient treatment couch; and a robotic armcoupled to the patient treatment couch, the robotic arm configured tomove the patient treatment couch along five rotational degrees offreedom and one substantially vertical, linear degree of freedom.
 2. Theapparatus of claim 1, wherein the patient treatment couch is made ofradiolucent material.
 3. The apparatus of claim 1, further comprising atleast one of a tilt sensor coupled to the patient treatment couch and anaccelerometer.
 4. The apparatus of claim 1, further comprising amounting plate coupled to the robotic arm and the patient treatmentcouch at an off-center position.
 5. The apparatus of claim 4, furthercomprising a dampener having dampening material coupled to the mountingplate and the patient treatment couch.
 6. The apparatus of claim 1,wherein the five degrees of freedom comprise: two rotational axes fortranslational movements of the patient treatment couch along mutuallyorthogonal horizontal coordinate x- and y-axes; and three rotationalaxes for roll-, pitch-, and yaw-rotational movements about the x-axis,the y-axis, and a z-axis, respectively.
 7. The apparatus of claim 6,wherein the one substantially vertical, linear degree of freedomcomprises a substantial linear axis for translational movements of thepatient treatment couch along a substantially vertical line in thez-axis substantially perpendicular to the horizontal coordinate x- andy-axes.
 8. The apparatus of claim 1, wherein the robotic arm comprises:a wrist assembly rotatably mounted to a mounting plate; an elbowassembly coupled to the wrist assembly; a shoulder assembly coupled tothe elbow assembly; a track mount assembly coupled to the shoulderassembly of the robotic arm; and a track coupled to the track mountassembly.
 9. The apparatus of claim 8, wherein the track is verticallyoriented.
 10. The apparatus of claim 9, wherein the track is coupled toa vertical side of a column.
 11. The apparatus of claim 8, wherein thewrist assembly comprises: a tool-yaw joint coupled to the mountingplate; a tool-pitch joint coupled to the tool-yaw joint; and a tool-rolljoint coupled to the tool-pitch joint.
 12. The apparatus of claim 11,wherein the tool-yaw joint is coupled to rotate the patient treatmentcouch along a z-axis, wherein the tool-pitch joint is coupled to rotatethe patient treatment couch along a y-axis, and wherein the tool-rolljoint is coupled to rotate the patient treatment couch along a x-axis.13. The apparatus of claim 12, wherein the elbow assembly comprises: afirst drive shaft coupled to the tool-yaw joint; a first motor coupledto the first drive shaft, the first motor configured to drive rotationalmovement of the tool-yaw joint of the robotic arm in a first rotationalaxis of the five degrees of freedom of the robotic arm; a second driveshaft coupled to the tool-pitch joint; a second motor coupled to thesecond drive shaft, the second motor configured to drive rotationalmovement of the tool-pitch joint of the robotic arm in a secondrotational axis of the five degrees of freedom of the robotic arm; athird drive shaft coupled to the tool-roll joint; and a third motorcoupled to the third drive shaft, the third motor configured to driverotational movement of the tool-roll joint of the robotic arm in a thirdrotational axis of the five degrees of freedom of the robotic arm. 14.The apparatus of claim 13, further comprising: an elbow joint coupled tothe elbow assembly and the shoulder assembly, wherein the elbow jointcomprises an elbow gearbox configured to drive rotational movement ofelbow assembly of the robotic arm in a fourth rotational axis of thefive degrees of freedom of the robotic arm; and a shoulder joint coupledto the shoulder assembly and the track mount assembly, wherein theshoulder joint comprises a shoulder gearbox configured to driverotational movement of the robotic arm in a fifth rotational axis of thefive degrees of freedom of the robotic arm.
 15. The apparatus of claim8, wherein the robotic arm is configured to move the patient treatmentcouch along an additional degree of freedom.
 16. The apparatus of claim15, wherein the five degrees of freedom and the additional degree offreedom comprise: three rotational axes for translations along mutuallyorthogonal x-, y-, and z-coordinate axes; and three rotational axes forroll-, pitch-, and yaw-rotations about x-, y-, and z-axes, respectively.17. The apparatus of claim 16, wherein the one substantially vertical,linear degree of freedom comprises a substantial linear axis fortranslational movement of the patient treatment couch along asubstantially vertical line in the z-axis substantially perpendicular tothe horizontal x- and y-axes.
 18. The apparatus of claim 17, furthercomprising: a plate member rotatably mounted on the track mount assemblyand the shoulder assembly; a first shoulder joint coupled to theshoulder assembly and the plate member, wherein the first shoulder jointcomprises a first shoulder gearbox configured to drive a fifthrotational axis of the six degrees of freedom of the robotic arm; and asecond shoulder joint coupled to the plate member and the track mountassembly, wherein the second shoulder joint comprises a second shouldergearbox configured to drive an sixth rotation axis of the six degrees offreedom of the robotic arm.
 19. A method, comprising: providing apatient treatment couch coupled to a robotic arm; and moving the patienttreatment couch along five rotational degrees of freedom and onesubstantially vertical, linear degree of freedom using the robotic arm.20. The method of claim 19, wherein the five rotational degrees offreedom comprise two rotational axes for translational movements andthree rotational axes for rotational movements including a yaw axis, apitch axis and a roll axis.
 21. The method of claim 20, furthercomprising moving the patient treatment couch along the substantiallyvertical, linear axis throughout substantially an entire range of motionof the patient treatment couch without moving the patient treatmentcouch along the five rotational degrees of freedom.
 22. The method ofclaim 20, wherein moving the patient treatment couch further comprises:rotating the patient treatment couch along the z-axis using a tool-yawjoint of the robotic arm; rotating the patient treatment couch along they-axis using a tool-pitch joint of the robotic arm; rotating the patienttreatment couch along the x-axis using a tool-roll joint of the roboticarm; rotating the patient treatment couch along the two horizontalrotational axes using a elbow joint and a shoulder joint; andtranslating the patient treatment couch along a substantially vertical,linear axis using a track and track mount assembly perpendicular to thetwo horizontal rotational axes.
 23. The method of claim 22, furthercomprising rotating the patient treatment couch along an additionaltranslational axis using an additional shoulder joint.
 24. An apparatus,comprising: a patient treatment couch; and a vertically mounted roboticarm coupled to the patient treatment couch at an off-center position.25. The apparatus of claim 24, wherein the off-center positioncomprises: an off-center length distance, the off-center length distanceis approximately 21 inches; and an off-center width distance, theoff-center width distance is approximately 4 inches.
 26. The apparatusof claim 24, wherein the vertically mounted robotic arm is configured tomove along at least five rotational degrees of freedom and onesubstantially vertical, linear degree of freedom.
 27. The apparatus ofclaim 24, wherein the vertically mounted robotic arm has a track mountassembly, the track mount assembly including a track mount collar,having a rear height at an end closest to the track of at leastapproximately eleven inches.
 28. An apparatus comprising: a patienttreatment couch; and means for supporting a patient on the patienttreatment couch up to five hundred pounds using a robotic arm within adeflection error of the robotic arm being approximately in a range ofzero to five millimeters.
 29. The apparatus of claim 28, furthercomprising: means for positioning the patient treatment couch in fiverotational degrees of freedom comprising two rotational axes fortranslational movements and three rotational axes for rotationalmovements; and means for positioning the patient treatment couch along asubstantially vertical, linear axis.
 30. The apparatus of claim 28,further comprising means for moving the patient treatment couch alongthe substantially vertical, linear axis throughout substantially anentire range of motion of the patient treatment couch without moving thepatient treatment couch along the five rotational degrees of freedom.